<UserControl x:Class="BookDemoApp.UCClipping"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:BookDemoApp">
  <DockPanel>
    <local:UCTitle DockPanel.Dock="Top" DataContext="Clipping" />
    <Rectangle Width="200" Height="300" Fill="Green">
      <Rectangle.Clip>
        <CombinedGeometry GeometryCombineMode="Exclude">
          <CombinedGeometry.Geometry1>
            <RectangleGeometry Rect="0 0 200 300" />
          </CombinedGeometry.Geometry1>
          <CombinedGeometry.Geometry2>
            <EllipseGeometry Center="100 150" RadiusX="70" RadiusY="100" />
          </CombinedGeometry.Geometry2>
        </CombinedGeometry>
      </Rectangle.Clip>
    </Rectangle>
  </DockPanel>
</UserControl>
